Siemens SIMATIC S7-300 Module data Reference Manual

Analog Modules
4-132
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
”Hardware filter 8 channels” mode
In “Hardware filter 8 channels” mode, the analog input module SM331; AI 8 x RTD
switches over between the two channels in each group. As the module contains
four analog/digital converters (ADC), all four of the ADCs convert simultaneously
for channels 0, 2, 4 and 6. Once the even-numbered channels have been
converted all the ADCs simultaneously convert for the odd-numbered channels 1,
3, 5 and 7 (see Figure 4-42).
Scan time
Start analog conversion
(simultaneous)
K0 K2 K4 K6
K1 K3 K5 K7
Start analog conversion
(simultaneous)
Figure 4-42 Hardware filter 8 channels scan time
Scan time of the module
In 8-channel hardware filter mode, the channel conversion time including the
communication time of the analog input module SM 331; AI 8 x RTD is 85 ms. The
module must then be switched over to the other channel in the group by means of
opto-MOS relays. Opto-MOS relays need 12 ms to switch and settle. Each
channel needs a time of 97 ms, so that the scan time is exactly 194 ms.
Scan time = (t
K
+ t
U
) x 2
Scan time = (85 ms + 12 ms) x 2
Scan time = 194 ms
t
K
: channel conversion time for one channel
t
U
: time for switching to the other channel in the channel group

Siemens SIMATIC S7-300 Module data Specifications

General

Series	S7-300
Manufacturer	Siemens
Protection Class	IP20
System	SIMATIC S7-300
Digital Inputs	Varies by module
Digital Outputs	Varies by module
Analog Inputs	Varies by module
Analog Outputs	Varies by module
Central Processing Unit	Varies by CPU model
Supply Voltage	24V DC or 120/230V AC
CPU Type	Varies (e.g., CPU 312, CPU 315, etc.)
Memory	Varies by CPU model
Communication Interfaces	MPI, PROFIBUS
Programming Languages	LAD, FBD, STL, SCL, GRAPH
Operating Temperature	0°C to 60°C
Storage Temperature	-40°C to 70°C
Relative Humidity	10% to 95% (non-condensing)